(a) Field of the Invention
An oxide semiconductor transistor that can be used in a pixel of a display device is provided.
(b) Description of the Related Art
Recently, research and development of a display device that is driven by a driving element using a-indium gallium zinc oxide (IGZO), which is an oxide semiconductor, have rapidly proceeded. Also, stability not only in driving of a display element but also according to mobility and a voltage current has been considerably researched and studied.
In this regard, a conventional display device driven by a driving element that uses existing a-Si is mainly used, but a driving element based on poly-Si has been applied to a display device. Since the poly-Si-based display device has high reliability due to current and strong voltage as well as high mobility, it is currently used in many products.
However, a conventional poly-Si-based semiconductor thin film transistor can provide a high performance characteristic only when using ELA crystallization, and the ELA equipment has problems of high unit production cost and maintenance cost.
Accordingly, an oxide semiconductor that can replace the semiconductor thin film transistor has been actively researched and studied. In this regard, recently, a display device that adopts a-IGZO, which is an oxide semiconductor, has been researched and developed, but mobility of the display device is as low as 10 cm2/Vs or less, and it is unstable in terms of positive bias temperature stress (PBTS) and high current temperature stress (HCTS), which are reliability factors of an oxide semiconductor thin film transistor.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.